LS2 Coil Problems

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750steve
MS/Extra Newbie
Posts: 21
Joined: Sat Jun 15, 2013 6:35 pm

LS2 Coil Problems

Post by 750steve »

Sorry I posted on an old thread that i found via google but maybe in here is more appropriate?

I seem to be having issues with these coils, & i've taken some values below, i've checked the wiring twice & it all looks correct!

I understand that from L to R with the tab at the BOTTOM the wiring is; 12V, 5V, ECU Signal Ground (the 4 coil wires from the ECU) & main ground, correct?

The coil fires when the ECU earths the 5V signal bringing it to under 1V, right?

I have checked the wiring over & over & its all as it should be, there is 12V at pin #1 when the ECU is on & the fuel pump relay is earthed, when the ECU finishes its startup mode after 4seconds (i think its 4s) the 12V disappears

Coils have been tried from 1.5mS to 3.5mS dwell

I used a voltmeter to get some readings when in TEST mode

ECU Switched on

At coil wire pin #2 (5V) & pin #3 (ECU Signal ground) when i hit TEST there is a positive voltage fluctuation (about 0.4V), so the ECU is earthing the 5V signal ok

At coil wire pin #3 (ECU Signal Ground) when the voltmeter is connected to it & directly to the 12V battery & TEST is pressed it shows 0.8V

At coil pin #1 (12V) & coil pin #4 (Main Ground) when the ECU is switched on there is 12.2V, when the ECU switches off & the Fuel Pump Relay is not earthed it goes to 0V

At coil pin #2 (5V) & pin #4 (main ground) there is 5V


So, the problem, my coils fire on startup but not on cranking, in TEST mode they won't fire either even though i know the ECU is earthing the 5V signal at the coil plug ok & i know the Fuel Pump Relay has to be active for the coils to get 12V

Heres a video https://www.youtube.com/watch?v=vNTiz2arth4

so can anyone tell me whats going on here? I absolutely baffled!!
GPz 750 Turbo Engine
Microsquirt V3.0, 2.920 Code
2 Crank Sensors, Single Tooth wheel
Wasted Spark
Ollie8974
Experienced MS/Extra'er
Posts: 238
Joined: Tue Aug 05, 2008 8:47 am

Re: LS2 Coil Problems

Post by Ollie8974 »

Video is marked as private, change it to public, so anyone can view it.
750steve
MS/Extra Newbie
Posts: 21
Joined: Sat Jun 15, 2013 6:35 pm

Re: LS2 Coil Problems

Post by 750steve »

Ok, that's done now, you should be able to see it.
GPz 750 Turbo Engine
Microsquirt V3.0, 2.920 Code
2 Crank Sensors, Single Tooth wheel
Wasted Spark
old guy
Experienced MS/Extra'er
Posts: 362
Joined: Thu Jan 24, 2008 9:20 am
Location: North Carolina

Re: LS2 Coil Problems

Post by old guy »

You have it wired wrong. it should be 12v,signal, the four wires from the ecu, sensor ground, main ground.
I think you are confused in that you are thinking that were the diagram shows 5v, it means the five volt signal that comes from the ecu to fire the coils. There is no 5v from the 5v supply going to the coil.
750steve
MS/Extra Newbie
Posts: 21
Joined: Sat Jun 15, 2013 6:35 pm

Re: LS2 Coil Problems

Post by 750steve »

Ok, thanks Guys!
GPz 750 Turbo Engine
Microsquirt V3.0, 2.920 Code
2 Crank Sensors, Single Tooth wheel
Wasted Spark
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